PBS’ follow up to Erin Brockovich left key details out

PBS NewsHour story on chromium contamination was short on context, long on fear.

Recently, PBS NewsHour ran a two-part investigative story that must have seemed to have all the elements of a compelling piece. There was a relatively unknown but apparently widespread carcinogen and a great hook—it was tied to the story of contaminated water behind the film Erin Brockovich. Issues relating to public health threats demand careful and thorough reporting. Unfortunately, those qualities were at times absent from the PBS story.

The story focused on hexavalent chromium (Cr6+) in drinking water. Most chromium is trivalent, which isn’t very soluble in water. When oxidized to hexavalent chromium, however, it becomes mobile. Unlike the trivalent variety, hexavalent chromium is carcinogenic. It's much worse if inhaled, but there’s evidence that it is dangerous when ingested as well. As the NewsHour story noted, recent sampling has shown that hexavalent chromium is present in drinking water across the country. Does that mean we have a public health crisis on our hands, caused by shockingly widespread contamination? Let’s slow down and get some context.

Meet the metal

Hexavalent chromium occurs naturally. That’s a rather important fact never mentioned in the NewsHour story, which describes the water as “tainted” by industrial chemicals. Chromium, like many elements, is present in Earth’s crust. Some types of rock have more than others, but it’s actually a little bit more common than copper or zinc—the average concentration in the upper crust is something like 90 parts per million. Oxidize some of that chromium to the hexavalent state, and it can be mobilized into groundwater. If hexavalent chromium is showing up in wells nearly everywhere we look, it might be because it’s naturally present rather than a ubiquitous, human-introduced contaminant.

This story has many California connections, from the town of Hinkley that Erin Brockovich fought to protect to the California EPA’s high-profile examination of hexavalent chromium health risks. But the connections extend to geology. Serpentinite—California’s state rock—is one of the best rocks in which to look for chromium ore.

California also has collected a lot of data on the occurrence of chromium in drinking water. Of 6,565 public water supply wells sampled across the state, hexavalent chromium was detected (meaning that the concentration was greater than 1 part per billion) in nearly half. It’s mostly present in the 1 to 8 parts per billion range, but it can be higher. In Hinkley, California determined that anything up to 3 parts per billion should be considered background rather than a result of the contamination there (contamination produced much higher concentrations).

While it can sound scary to hear that a potentially hazardous compound was detected in your water, it’s the concentration that determines the risk. The NewsHour story focused on a study of hexavalent chromium in water around a chromium ore mining operation in China. The 1987 study found a statistically significant increase in certain cancer rates for the villages with higher concentrations of hexavalent chromium in their water. Ergo, the story implies, the hexavalent chromium in your water may be giving you cancer, too.

But the concentrations in those Chinese villages were astronomical—as high as 20,000 parts per billion. A summary in the journal Epidemiology describes it as “perhaps the highest exposure to hexavalent chromium in water that will ever be experienced by a population large enough to estimate risks of cancer.” A pair of studies on populations in the US with low-level exposures failed to find much of a correlation—although one did find a slight link to lung cancer. (Again, the risk from inhalation is better understood.) Laboratory studies with rats have indeed shown hexavalent chromium in water to be carcinogenic, but extrapolating this sort of result down to small doses is often tough.

A 2010 Environmental Working Group study sampled water from 35 US cities and reported that hexavalent chromium had been detected in 31 of those cities. But at what concentrations? Only one city had concentrations greater than 2 parts per billion—Norman, Oklahoma at 12.9 parts per billion. A recently completed study that followed up on the results in Madison, WI found concentrations of up to 2 parts per billion in municipal wells—and chromium as high as 30,000 parts per billion in bedrock samples from those wells. The evidence points to a natural source for the hexavalent chromium in the water.

The EPA drinking water standard for total chromium is 100 parts per billion, but that standard is currently being reviewed. California has chosen a “Public Health Goal” of 0.02 parts per billion. We often think of such standards as the line between safe and unsafe exposures, but the real world isn’t so cut-and-dried. The eventual drinking water standard will only be set as close to the Public Health Goal “as is economically and technically feasible.” And the Public Health Goal for hexavalent chromium is based on a one-in-a-million cancer risk. That is, “for every million people who drink two liters of water with that level of [hexavalent chromium] daily for 70 years, no more than one person would be expected to develop cancer from exposure to [hexavalent chromium].”

All these complexities—natural sources, levels of exposure, etc.—were largely left out of the NewsHour report.

At one point in the NewsHour story, Erin Brockovich talks about a crowd-sourced map of cancer clusters she has organized. Her assertion that hexavalent chromium in drinking water is likely the cause of most of the cancer hotspots went completely unchallenged. And the concept itself relies on the dubious assumption that the clusters have local causes. (In reality, cancer clusters are often statistical flukes.) It also assumes that hexavalent chromium is the result of industrial contamination rather than occurring naturally across broad regions.

As anthropogenic groundwater contaminants go, hexavalent chromium isn’t terribly common—unlike petroleum or chlorinated solvents. It’s hard to imagine that industrial releases of hexavalent chromium could be impacting such an astounding number of public wells. If the hexavalent chromium is naturally occurring, the discussion about what’s acceptable and what to do about it becomes a lot more nuanced. Nuance is not what the NewsHour report delivered.

Muddying the waters

It isn’t the first story ever to lack appropriate context, so why has it drawn my ire? Stories like this scare the bejeezus out of people. In a blog post accompanying his story, reporter Miles O’Brien reveals that he had the tap water in his apartment tested while working on this story. When the results showed a concentration of 0.19 parts per billion, he started filtering his water for fear of the cancer risk. After all, as he puts it, “That is ten times more [hexavalent chromium] than the Cal/EPA public health goal.” (A related post helps readers select an expensive filtration system of their own.)

The Environmental Working Group study mentioned above that found hexavalent chromium in 31 cities claims that “[a]t least 74 million Americans in 42 states drink chromium-polluted tap water, much of it likely in the cancer-causing hexavalent form.” Still thirsty? How many people are going to start buying bottled water because of this—water that simply comes from a well somewhere else and might contain just as much hexavalent chromium?

Apart from frightening people who already lead stress-filled lives, claims like this can undermine the actual science (as well as the journalists reporting it). We’ve all heard someone dismiss a health report with, “Whatever, they say everything gives you cancer.”

This particular presentation also chose a common storyline: it pitted plucky environmental watchdogs against corporate mouthpieces. While it may make for good TV, it’s not the best way to establish the facts. What if the corporate lobbyist is right about something? What if the environmental advocate is mistaken? It’s ultimately the journalist’s responsibility to find the experts who can present both the evidence and the uncertainty, rather than letting interested parties have their say unchallenged.

In this shallow, adversarial context, emotions often come to the forefront. And places where contamination has occurred, like Hinkley, provide examples of how damaging these emotions can be. Residents can feel scared, frustrated, and helpless. They’re suddenly exposed to a torrent of new information they have to absorb. They want to protect themselves and their families, and they’re wary of dishonesty and corruption. Trust breaks down, and misunderstanding runs amok.

The story mentions that residents of Hinkley are now terrified that they’re being poisoned with arsenic and manganese, as well—something they blame on the facility that caused the hexavalent chromium contamination. There’s a pretty good chance that these elements had naturally been present all along but hadn’t been tested for or drawn attention before.

It’s so difficult to inject complex facts and rational evaluation into charged issues like this, which makes it all the more critical that media reports take care to do so. While the NewsHour story raises fair questions about industry interference with the development of a hexavalent chromium public health standard, it also fans the flames of chemophobia. The intent was undoubtedly to inform, but the result was confusion.

When Ars asked NewsHour to comment on these concerns, a spokesperson for the program responded, "The Newshour’s two-part report on chromium 6 in drinking water supplies examined arguments about levels of safety and about the EPA’s process for making that determination. We included different points of view in our reports: those of affected residents, environmental activists, industry spokespeople, and scientists. The EPA refused to grant an interview, and we did our best to represent the agency’s position. Any specific comment should be viewed in the context of the entire report."

But that approach—letting everyone have their say, without any critical evaluation—is part of the problem. This is not a question of differing points of view, but one of carefully sifting the knowns and unknowns. Presenting opposing perspectives and leaving the viewer to decide is not the way to communicate science, and it doesn't excuse broadcasting misleading or incomplete information.

This article mistakenly referenced the book "A Civil Action" as the basis for the film "Erin Brockovich". The book, which became a movie of the same name, was written about a lawsuit over chlorinated solvent contamination in Woburn, Massachussets.

Note: While I am employed by the Wisconsin Department of Natural Resources, views expressed are my own and should in no way be construed as representing the department.

155 Reader Comments

Reminds me of the dihydrogenoxid health scare. A chemical that is found in water and can be deadly if consumed in large quantities.

But seriously my main pet pieve about all these chemicals everywhere nutjobs is that they do not seem to notice that everything surrounding us is a chemical. Human or natural. (fits that it was in California as well)

This also reminds me of the silicone breast implant scare which lead to bankruptcies, massive payouts, and unnecessary medical procedures. All before the science came in and the product was quietly reintroduced. Or the supposed cancer clusters from power lines.

The list goes on and on. Emotion from anecdote seems to always trump the reality from science.

Another point often missed in these reports is that our laboratory instruments and field sensors are getting incredibly good at detecting very low concentrations. So an important question to ask is "Is this concentration new/rising or are we just newly able to detect it." Some historical regulatory levels were in fact just set to or near the minimum detection levels of available technology.

And there in lies the problem. Most of these broadcasts and publications aren't about science or facts. It's about ratings. Facts are boring. Controversy makes for good TV. We are all to blame, as we become less educated and bombarded with information, we neglect to hold people accountable, be they politicians, journalists and broadcasters, and instead simply clamor for entertainment, sometimes in the guise of "science." I don't pretend to think we have enough hours in the day to individually fact check every story about our world that comes across the wires, but the sources of objective peer-review accessible to the (becoming more uneducated) masses are dwindling, and I believe you can make the argument that as goes journalistic integrity, so goes fact-based emotionless civil discourse.

PBS NewsHour is not a science education program. It sounds like the author needs a reminder of that. The fact is that while they clearly misrepresented or omitted important information, the goal of the program is to deliver news, not to fully educate about hydrology, geology, or biology.

The fact is that there isn't a lot of scientific certainty about safe levels of ingested hexavalent chromium. Nobody really knows what is safe and what isn't. More research is required, obviously, before "science" can be presented in that area. Holding a TV news program's feet to the fire for not presenting "science" where little science actually exists is just silly.

"Water pumped out of the ground may contain trace quantities of naturally occurring minerals" is not news. It becomes news if those minerals are present at harmful levels, or if there is contamination. If you don't have anything to say on those topics, you don't have a news story. I'm not saying you need to spend an hour on science education, but "news" with no context at all is not news, whether the required context is science, politics, or history.

And there in lies the problem. Most of these broadcasts and publications aren't about science or facts. It's about ratings. Facts are boring. Controversy makes for good TV. We are all to blame, as we become less educated and bombarded with information, we neglect to hold people accountable, be they politicians, journalists and broadcasters, and instead simply clamor for entertainment, sometimes in the guise of "science." I don't pretend to think we have enough hours in the day to individually fact check every story about our world that comes across the wires, but the sources of objective peer-review accessible to the (becoming more uneducated) masses are dwindling, and I believe you can make the argument that as goes journalistic integrity, so goes fact-based emotionless civil discourse.

Thanks for calling out NewsHour's report. Many programs throw a bunch of opinions at the audience and pretend it’s journalism. It happens all the time and I wish it would change, but for some reason I expect better from PBS.

I enjoyed this article, but more for the coverage on water contamination, how it is tracked, and how it is kept safe rather than the dressing down of PBS. At this point in my life I take any mainstream media analysis of science with a huge lump of salt.

Please write another article that talks about how the US keeps our drinking water safe, what dangers they look for, and how they coordinate those efforts with businesses. Cheers.

I think the authors story here is not only about how they went about doing it and why, but that it was PBS. A lot of people, myself among them, tend to look at PBS(with a less jaded eye or mindset) as more of a trusted type of place for news of this nature and not just going for the gusto or scare tactics like so many other cable news channels do now.

At least that was my partial take on the article along with what else was brought up.

PBS NewsHour is not a science education program. It sounds like the author needs a reminder of that. The fact is that while they clearly misrepresented or omitted important information, the goal of the program is to deliver news, not to fully educate about hydrology, geology, or biology.

The fact is that there isn't a lot of scientific certainty about safe levels of ingested hexavalent chromium. Nobody really knows what is safe and what isn't. More research is required, obviously, before "science" can be presented in that area. Holding a TV news program's feet to the fire for not presenting "science" where little science actually exists is just silly.

This comment is bad in soo many ways I don't know where to begin. If "PBS NewsHour is not a science education program" then they should not be making scientific claims. Misleading information is often far more dangerous than no information

It is a shame Ars isn't required reading, if it was people might understand that science is in the details not the emotions.

Sorry but Ars readers are just as guilty of making "science" arguments based on emotion and guilt and not on hard facts. You will find it on every social news site. Ars is not immune simply because you happen to like it.

Chaos warrior - the point is that the science makes this non-news. Or at the very least, requiring a whole lot more information before it becomes something I'd want to see on newshour. I still think that one incomplete program doesn't mean that PBS is like Fox and Friends, but it does mean that Ars is required reading for any science story that makes the news anywhere. Thanks for doing the hard work I don't have the time for.

One of the core issues in science journalism is the lack of scientific training - even basic university courses - among journalists and their editors generally. This a particular issue for reporting that is aimed at a general audience - even a fairly educated one like PBS. Even if the reporter is a competent and responsible with the science content, it often gets diluted or shifted in the editing process. While much of the U.S. population is functionally illiterate in STEM subjects, journalists seem to be more so despite a curriculum that is designed to give them a broad grounding*.

Add to this the core belief in modern "objective" journalism philosophy that "both" sides should get their say and you have a recipe for malpractice. It think this lack of background and understanding are the foundation for why science reporting specifically and the wider public discourse in general, are argued from an emotional basis rather than a rational basis.

I say this as someone with over a decade in newspapers editorial departments, now working for a research organization.

The story mentions that residents of Hinkley are now terrified that they’re being poisoned with arsenic and manganese, as well—something they blame on the facility that caused the hexavalent chromium contamination. There’s a pretty good chance that these elements had naturally been present all along but hadn’t been tested for or drawn attention before.

Just as likely, the contamination came from old mining sites. I can think of one site in particular just off US 395 not far all that far from Hinkley that has mine tailings loaded with arsenic. While the main primary resulting contamination from that type of site is airborne, it is fairly common for groundwater contamination to be linked to old mining sites.

The Mojave desert (where Hinkley is located) is full of mining, industrial, and military sties, both abandoned and active, that contribute heavily to groundwater and air contamination. It's a widespread problem not restricted to the California desert. Hinkley was the unlucky location of an acute concentration of contamination. Add an exceptionally large legal settlement and a blockbuster movie and you wind up with some long-lasting hype.

I haven't seen the NewsHour in question. That being said, I have always considered PBS programs to be relatively unbiased in comparison to similar shows on the major networks. I would be extremely disappointed if NewsHour didn't point out that Erin Brockovich has made A LOT of money off litigation involving hexavalent chromium. Portraying her as an activist, instead of a party with a significant financial interest, would not reflect well on PBS.

PBS NewsHour is not a science education program. It sounds like the author needs a reminder of that. The fact is that while they clearly misrepresented or omitted important information, the goal of the program is to deliver news, not to fully educate about hydrology, geology, or biology.

So misrepresenting the facts and passing it off as news is fine, so long as the way it's done is "fair and balanced", right?

" That is, “for every million people who drink two liters of water with that level of [hexavalent chromium] daily for 70 years, no more than one person would be expected to develop cancer from exposure to [hexavalent chromium].”

This probably also uses a linear, no threshold dose model, which assumes that at one-one millionth the dose you get one-one millionth the effect. But there is often a threshold below which there is no effect.

" That is, “for every million people who drink two liters of water with that level of [hexavalent chromium] daily for 70 years, no more than one person would be expected to develop cancer from exposure to [hexavalent chromium].”

This probably also uses a linear, no threshold dose model, which assumes that at one-one millionth the dose you get one-one millionth the effect. But there is often a threshold below which there is no effect.

The point of this piece was less that chromium 6 is dangerous, and more that EPA - Chemo Industrial complex is setup in such a way as to make such a determination impossible, as the focus is always on what is economically feasible, not what is actually safe. Yes, it's a confusing mess - because if it wasn't we might have to do something about that, and that something might cost some one some money.

This was indeed the point of the PBS piece, and it leaped out at me when reading it here, too. It's not "what's safe?" but "what's economically feasible that won't obviously kill everyone?" Those are two very different things.

While this article is a self-described rant, it unfortunately has the major hallmark of a rant: missing the point.

Is economic feasibility really a bad way to determine allowed levels of chemicals in water?

The other thing that people forget is that true randomness will exhibit clusters. In fact should clusters not exist, it isn't random. So when I hear "OMG it's a cancer cluster - must be XYZ"; my BS meter pegs.

This also reminds me of the silicone breast implant scare which lead to bankruptcies, massive payouts, and unnecessary medical procedures. All before the science came in and the product was quietly reintroduced. Or the supposed cancer clusters from power lines.

The list goes on and on. Emotion from anecdote seems to always trump the reality from science.

Maybe you haven't been following the news, but there was another silicon breast implant scandal that affected tens of thousands of women (via a manufacturer in France). It's on going.

But that approach—letting everyone have their say, without any critical evaluation—is part of the problem. This is not a question of differing points of view, but one of carefully sifting the knowns and unknowns. Presenting opposing perspectives and leaving the viewer to decide is not the way to communicate science, and it doesn't excuse broadcasting misleading or incomplete information.

And the problem I have with Journalists drawing conclusions is that they bring their own bias into the discussion or article and all too often it ceases to about balanced science and rather about directing the reader to take sides rather than to be informed about the perspectives of both sides. Granted leaving out critical details can be just as bad as trying to direct the reader to take up a particular opinion but I for one do NOT want journalist telling me to think this way or that. give me the facts and let me decide how to act. Its really an impossible position for a reporter to be in though when it comes to critical complex sitiuations like this. Somewhere along the line some important related info is going to be skipped or missed that paints the situation in a different light and can lead reader to a conclusion different than full disclosure might have otherwise provided.